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<P class="title">Advanced compression parameters<hr></P>

<P>This dialog contains a number of advanced compression options
for RAR archive format. Their improper use may lead to suboptimal
performance and compression. These options are described below.</P>

<h1><b>Long range search</b></h1>

<p>Enables the search algorithm designed to efficiently locate longer
and more distant repeated data blocks. It can helps to improve the compression
ratio and sometimes speed for redundant data like big text files.
This algorithm increases memory requirements when archiving, but doesn't
affect extraction memory requirements or speed.</p>

<p>If "Auto" is selected, WinRAR applies the long range search depending
on the compression method, <a href="HELPGetArcGeneral.htm#DictSize">dictionary
size</a> and other parameters. "Always on" turns it on permanently. "Disable"
turns it off. This algorithm is required and enabled automatically
for dictionaries exceeding 4 GB, ignoring "Disable" option.</p>

<p>Long range search mode is applicable to "Fast" .. "Best" compression
methods and ignored for "Fastest" one.</p>

<h1><b>Delta compression</b></h1>

<p>Splits data to several single byte channels and calculates the difference
between them. Can improve the compression ratio of table data.</p>

<p>"Auto" mode applies it depending on the compression method. "Always on"
turns it on permanently. "Disable" turns it off.</p>

<h1><b>x86 executable compression</b></h1>

<p>Can improve the compression ratio of 32 and 64 bit x86 executables.</p>

<p>"Auto" mode applies it depending on the compression method. "Always on"
turns it on permanently. "Disable" turns it off.</p>

<h1><b>Exhaustive search</b></h1>

<p>Enables much slower and more exhaustive repeated data search
and compression algorithm. It might provide the additional compression gain
on some types of redundant data, but at much lower speed. Long range search
is needed to implement this mode efficiently, so the exhaustive search option
activates it automatically.</p>

<h1><I>Default button</I></h1>
<p>Reset all options of this dialog to default values.</p>

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